By careful comparison of mismatched vanishing lines, identify that the companion cube is actually a hypercube resting in a different spacial plane than the purple room. Hug the cube, kick off from the floor, and fly away into a different universe!

STICK HEAD into next room. Is it this room?Examine INSIDE EDGE of PORTAL. Rewire COSMIC PORTAL EDGE ENERGY into NEW, SHINY TIME DEVICE.Use the device to TELEPORT COMPANION CUBE into an INCINERATOR.If a door doesn't open after this, CRY.